40 clinical MCQs in Biochemistry. Indicate the name and write a detailed reaction that is catalysed by each of the following. Kenya, Africa and global r...
-
Q1. Indicate the name and write a detailed reaction that is catalysed by each of the following enzymes and clearly indicating whether the reaction is reversible or irreversible ---
- G3P to DHAP converting enzyme.
- OAA and acetylCoA condensing enzyme.
- A PEP carboxylating enzyme.
- Isocitrate cleavage enzyme
- An enzyme associated with favism
Answer: G3P to DHAP converting enzyme.
-
Q2. The following are all oxygen containing functional groups, except ---
- Alcohol
- Aldehyde
- Ketone
- Thiols
- Ethers
Answer: Alcohol
-
Q3. An ester functional group can best be represented as ---
- $-$CHO
- $-$COOH
- $-$COOR
- $-$CONH$_2$
- $-$COC
Answer: $-$CHO
-
Q4. All the following lipids are found in animal membranes ---
- Phosphoglycerides
- Cholesterol
- Triacylglycerols
- Glycolipids
- Sphingolipids
Answer: Phosphoglycerides
-
Q5. The solubility of alcohols in water ---
- Increases as the carbon chain length increases.
- Decreases as the number of $-$OH groups present increases
- Increases with increasing molecular mass
- Is a result of H-bonding between alcohol and water molecules
- Is greater than that of carboxylic acids of equal molecular mass
Answer: Increases as the carbon chain length increases.
-
Q6. From the major precursors, the complex biomolecules are made in the following sequence ---
- metabolites, building blocks, macromolecules, supramolecular complexes
- macromolecules, building blocks, metabolites, supramolecular complexes
- building blocks, macromolecules, supramolecular complexes, metabolites
- metabolites, macromolecules, building blocks, supramolecular complexes
- building blocks, macromolecules, metabolites, supramolecular complexes
Answer: metabolites, building blocks, macromolecules, supramolecular complexes
-
Q7. One of the following carbohydrates will test positive with Fehlings solution ---
- Trehalose
- Starch
- Lactose
- Sucrose
- Raffinose
Answer: Trehalose
-
Q8. Which of the following weak acids would make the best buffer at $\text{pH} = 5.0$? ---
- Acetic acid ($\text{Ka}=1.74 \text{ x } 10\text{-}5$, $\text{pka} = 4.76$)
- $\text{H}_2\text{PO}_4^-$ ($\text{Ka}=1.38\text{x}10^{-7}$, $\text{pka} = 7.20$)
- Bicarbonate ($\text{Ka} = 6.3\text{x}10^{-11}$, $\text{pka} = 10.24$)
- Tris-hydroxymethylaminomethane ($\text{Ka}=8.32\text{x}10^{-9}$, $\text{pka}=8.07$)
- Lactic acid ($\text{Ka} = 1.38\text{x }10^{-4}$, $\text{pka}=3.86$)
Answer: Acetic acid ($\text{Ka}=1.74 \text{ x } 10\text{-}5$, $\text{pka} = 4.76$)
-
Q9. At physiological pH (7.4), the R-groups of one of the following amino acids would carry a net negative charge? Aspartic acid and Arginine ---
- Glutamic acid and Histidine
- Histidine nad Arginine
- Lysine and Arginine
- Asparate and glutamate
Answer: Glutamic acid and Histidine
-
Q10. The function of attached ribosomes to RER is to synthesize ---
- lipid
- carbohydrate
- Protein that will be secreted by the cell
- cytoplasmic protein necessary for the cell own existence
- glycogen
Answer: lipid
-
Q11. The conversion of arachidonic acid to prostagladins and thromboxanes is mediated by? ---
- Lipoxygenase
- Cyclooxgenase(s)
- Phospholipase A2
- Diacylglycerollipase(s)
- Cytochrome P450
Answer: Lipoxygenase
-
Q12. Denaturation of proteins results in ---
- Disruption of primary structure
- Breakdown of peptide bonds
- Destruction of hydrogen bonds
- Irreversible changes in the molecule
- Folding of the protein native structure Reg. No.: .....................................
Answer: Disruption of primary structure
-
Q13. The following statements are true regarding carbohydrates, except ---
- Serve as energy stores in plants and animals
- Are major structural components of mammalian tissues
- Are constituents of nucleic acids
- Are conjugated to many proteins and lipids
- Are found in the structure of all amino acids
Answer: Serve as energy stores in plants and animals
-
Q14. The following separation techniques exploits differences in net charges of proteins at a given pH ---
- Thin layer chromatography ion exchange chromatography
- Ion exchange chromatography and electrophoresis
- High performance liquid chromatography
- Paper chromatography and electrophoresis
- Thin layer chromatography and electrophoresis
Answer: Thin layer chromatography ion exchange chromatography
-
Q15. One of the following contains an ether-linked alkyl group? ---
- Cerebrosides
- Gangliosides
- Phosphatidyl serine
- Platelet-activating factor
- Sphingomyelin
Answer: Cerebrosides
-
Q16. The following are examples of structural polysaccharides ---
- Chitin
- Glycogen
- Cellulose
- Peptidoglycan
- Starch
Answer: Chitin
-
Q17. The purpose of hydrophilic R group of an enzyme is ---
- to help in protein molecule coil in three dimensional space
- to prevent the enzyme from being denatured at higher temperatures.
- To ensure that they are soluble in fats
- To add stability of the enzyme
- To ensure they are soluble in water
Answer: to help in protein molecule coil in three dimensional space
-
Q18. The more modern hypothesis about enzyme action is called ---
- induced fit hypothesis
- lock and key hypothesis
- lock and substrate hypothesis
- enzyme substrate hypothesis
- inhibitor-enzyme-substrate hypothesis Reg. No.: .....................................
Answer: induced fit hypothesis
-
Q19. Enzyme catalyzing rearrangement of atomic groupings without altering molecular weight or number of atoms is ---
- Hydrolase
- Oxidoreductase
- Isomerase
- Ligase
- Transferase
Answer: Hydrolase
-
Q20. Vitamin $\text{B} 1$ is called ---
- Pyridoxin
- Thiamine
- Thymine
- Niacin
- Retinol
Answer: Pyridoxin
-
Q21. Vitamin $\text{B} 2$ is called ---
- niacin
- riboflavin
- thymine
- thiamine
- calcepherol
Answer: niacin
-
Q22. Which of the following vitamin is essential for the development of red blood cells? ---
- Vitamin C
- Vitamin K
- Vitamin $\text{B}_6$
- Vitamin A
- Vitamin $\text{B}_{12}$
Answer: Vitamin C
-
Q23. Which of the following vitamin helps in coagulation of blood? ---
- Vitamin E
- Vitamin C
- Vitamin K
- Vitamin B1
- Niacin
Answer: Vitamin E
-
Q24. Which of the following vitamin deficiency causes pellagra? ---
- Vitamin K
- Vitamin A
- Vitamin $\text{B}_3$ (niacin)
- Vitamin D
- Vitamin $\text{B}_{12}$ Reg. No.: ....................................
Answer: Vitamin K
-
Q25. Deficiency of Vitamin C causes ---
- right blindness
- anemia
- beriberi
- scurvy
- rickets
Answer: right blindness
-
Q26. Overdose of Vitamin A and Vitamin D causes ---
- rickets
- scurvy
- hypervitaminosis
- anemia
- headache
Answer: rickets
-
Q27. Which of the following has a thioester bond/linkage? ---
- PEP
- ATP
- ActylCoA
- Pyruvate
- Phosphocreatine
Answer: PEP
-
Q28. Which of the following can catalyse the conversion of AMP to ADP? ---
- Hexokinase
- Adenylate kinase
- Nucleoside diphosphate kinase
- Cytidylate kinase
- None of the above
Answer: Hexokinase
-
Q29. Which of the following pair of compounds may be used in anaplerotic reaction(s)? ---
- Odd chain fatty acids and amino acids
- Odd chain fatty acids and acetylCoA
- Even chain fatty acids and amino acids
- Even chain fatty acids and acetylCoA
- AcetylCoA and amino acids
Answer: Odd chain fatty acids and amino acids
-
Q30. NADPH is not made in the ---
- Liver
- Mammary glands
- Buttocks
- Adipose tissue
- Skeletal muscle Reg. No.: .....................................
Answer: Liver
-
Q31. Which of the following is not true? ---
- Cholesterol is made from three molecules of acetylCoA
- Cholesterol synthesis is suppressed by dietary cholesterol
- Cholesterol is transported to specific areas as lipoproteins
- Absence of the LDL receptor may lead of hypercholesterolemia and/or atherosclerosis
- A competitive inhibitor of HMGCCoA reductase slows cholesterol synthesis
Answer: Cholesterol is made from three molecules of acetylCoA
-
Q32. Alpha-ketoglutarate dehydrogenase reaction is omitted in ---
- Gluconeogenesis
- The TCA cycle
- The glyoxylate cycle
- The urea cycle
- An anaplerotic reaction involving $\alpha$-kg
Answer: Gluconeogenesis
-
Q33. Unlike glucokinase, hexokinase ---
- Catalyses the phosphorylation of all hexoses including galactose
- Has a lower $k_m$ for glucose
- Is allosterically inhibited by G6P
- Is deficient in diabetes mellitus
- Is found in many tissues Which of the above is incorrect?
Answer: Catalyses the phosphorylation of all hexoses including galactose
-
Q34. Ribose 5-phosphate and its derivatives are components of such important biomolecules as ---
- NAD
- FAD
- FMN
- CoA-SH
- All the above
Answer: NAD
-
Q35. The following compound does not participate in the entry of galactose into the glycolytic pathway ---
- G6P
- G1P
- UTP
- UDP-galactose/ glucose 1-phosphate uridylyltransferase (GALT)
- Phosphoglucomutase
Answer: G6P
-
Q36. is added to diacylglycerol to form a triacylglycerol ---
- DHAP
- AcetylCoA
- Glycerol 3-phosphate
- Fatty acid
- Fatty acylCoA
Answer: DHAP
-
Q37. Glycogen storage disease (GSD) type I is also known as disease ---
- Pompe's
- Gierke's
- Tarui's
- Cori's
- Forbe's
Answer: Pompe's
-
Q38. Which of the following GSD is not associated with glycogenolysis but with glycogenesis? ---
- Type I
- Type III
- Type IV
- Type O
- Type II
Answer: Type I
-
Q39. Which of the following poison would interfere with the efflux of ATP from the mitochondrial matrix to the cytosol? ---
- Bongkrekate
- Atractyloside
- Antimycin A
- Rotenone
- Cyanide
Answer: Bongkrekate
-
Q40. Which of the following is not true about glycogenin?
- Is a polypeptide with an essential tyrosine residue?
- It catalyses elf-glucosylation
- Promotes an O-linked glucosylation with loss of $\text{H}_2\text{O}$
- It has an inherent enzyme activity.
- Is involved in addition of each glucosyl residue to a growing glycogen chain --- Source: biochemistry/questions/bchem EOY 2015.pdf.
Answer: Is a polypeptide with an essential tyrosine residue?